Photojournalist Jo-Anne McArthur travels around the world collecting grim photographs and video footage of animals suffering in pet mills and factory farms, images that are liberally sampled in this documentary by Liz Marshall. At one point McArthur, a hardcore vegan and animal-rights crusader, shares her childhood memory of growing up with chickens and individualizing each of them, a perspective some will find extreme. Yet Marshall works overtime to realize it onscreen, focusing tightly on the emotional lives of exploited animals as they plod through their miserable existences to slaughter. (The ones lucky enough to have room to plod, that is.) In the movie’s introductory sequence, one observer notes that animals have no intellect and therefore can’t be considered on the same plane as humans, but that’s the only dissenting opinion in a movie whose open agenda is animal liberation.